Paper particles may be applied to the surfaces of offset printed documents in order to prevent printed materials from coming into contact with each other, and prevent ink smear on the back surface caused by such printed materials coming into contact with each other. When such a document is conveyed by a document conveying apparatus such as a scanner apparatus, the paper particles that stick to the surface of the document adhere to a roller for conveying the document, which reduces the friction coefficient of rubber, and may reduce the conveying performance.
A feeding roller in which many grooves and many groove projections of which cross section forms an asymmetrical waveform shape are formed on an external periphery in a direction perpendicular to a paper conveying direction is disclosed (see Japanese Patent No. 3429878).
A paper feeding roller in which multiple recessed grooves extending in an axial direction on an external periphery of an elastic layer are formed with a predetermined pitch in a peripheral direction, and the external peripheral other than the recessed grooves of the elastic layer and bottom surfaces and side wall surfaces of the recessed grooves are formed into an emboss surface constituted by projection shaped portions and recess shaped portions is disclosed (see Japanese Patent No. 4042806).
A paper feeding roller in which recesses and projections are provided on the roller surface and only the inner peripheral surfaces of the recessed portions are halogenated is disclosed (see Japanese Laid-open Patent Publication No. H11-106067).
A feeding roller having spherical silicone powder and/or polar silicone oil mixed in high-polymer material is disclosed (see Japanese Laid-open Patent Publication No. 2000-118778).
A conveying roller in which surface processing such as emboss processing, knurling processing, groove processing is applied as necessary to the surface of a rubber elastic body is disclosed (see Japanese Laid-open Patent Publication No. 2013-095540).